2021 Honda CRF450RX: EMBRACE WINNING, ON OUR BEST ENDURO EVER.
Introducing the 2021 Honda CRF450RX…
Ridden by Phoenix Racing Honda, SLR Honda and JCR Honda at the national-championship level, the CRF450RX is well-suited for closed-course off-road competition such as GNCC, WORCS and NGPC. For the 2021 model year, it’s better than ever, getting the same important performance upgrades as the motocross-focused CRF450R and retaining off-road-specific features like dedicated ECU and suspension settings, an 18-inch rear wheel and an aluminum side stand. New for 2021, the CRF450RX comes standard with handguards and a revised 2.1 gallon fuel tank that narrows the bike width at the radiator shrouds. The combination yields a race machine that’s ready to chase arrows and ribbon along trails from coast to coast.
THE REDESIGNED 2021 CRF450RX
Enduro racing is an ever-changing challenge—the terrain, the competition, the weather, the course. And you can’t be static in a changing environment if you want to prevail. That’s why we’ve given the class-leading Honda CRF450RX so many big changes this year. Basically, it gets all the same awesome upgrades as our CRF450R: new frame, cylinder head, hydraulic clutch, clutch internals, fuel injection, single-muffler exhaust, and more. Plus we’ve fine-tuned the suspension specifically for enduro riders, shaved approximately four pounds off last year’s bike, and even hooked you up with factory handguards. All in all, it’s the highest performing bike we’ve ever offered in the class. Embrace the changes—then embrace victory.
2021 Honda CRF450RX Totalmotorcycle.com Key Feature
TRACTION MACHINE
Just like the CRF450R, the CRF450RX has a new frame, steering geometry and suspension setup developed directly from HRC’s race bikes, so you can go in harder and come out faster. The engine also features more power with smoother torque delivery controlled by hydraulic clutch. The 3-Level HRC Launch Control gives you options out of the gate whatever your riding ability or experience, and whatever conditions you’re riding in. And once you’ve bossed the start, 3-Level Honda Selectable Torque Control (HSTC) keeps you driving forward.
THE TOOL OF CHOICE
Start with the best there is. Then make it better.
With the CRF450R MX machine as a base the CRF450RX already has an advantage and, along with its enduro-specific equipment – larger fuel tank, 18-inch rear wheel and sidestand. A completely new frame saves weight and features factory-rider rigidity balance with sharper steering, extra ground clearance and RX-specific suspension settings. The seat unit is smaller (and lower at the back) and new plastics are slimmer, lighter and easier to move around. For stronger mid-range power and smooth throttle response, the engine has a redesigned intake, cylinder head and exhaust while a revised decompression system minimises stalling. The new hydraulic clutch is tougher, with lighter lever load. HRC Launch Control owns the first 100 metres and HSTC manages rear wheel traction over a lap.
MALL CHANGES. BIG GAINS
More speed to cut time. What else matters?
Go in harder. Come out faster. Do it over.
The new CRF450RX begins life in the same place as the 2021 CRF450R – so it’s based heavily on Tim Gajser’s 2019 MXGP championship-winning HRC machine. Not a bad place to start. Showa’s 49mm USD coil spring fork has an extra 5mm stroke and the axle clamps’ rigidity increased. Larger main piston valving in the Showa rear shock gives improved bump absorption and faster response, and the Pro-Link ratio is also new. As a whole, the CRF450RX is 2.3kg lighter – which you notice, instantly. Narrower main spars and a redesigned subframe save just over 1kg between them. Most importantly, what you feel has been heightened; the rib positions behind the swingarm pivot points have been changed and, with torsional rigidity maintained, lateral rigidity is reduced 20% to increase corner speed, traction and steering accuracy. Tighter geometry gives sharper steering and more ground clearance.
Smooth engine power you can use.
Twin exhaust ports use an ovalized exit and a new, single downpipe and muffler save 1.24kg. There’s more power from 5,000rpm up and for stronger, smoother low-rpm torque, the airbox is larger with tool-free access to the filter. For optimised intake efficiency it feeds a redesigned throttle body and a steeper injector angle sprays fuel all the way back to the butterfly, improving feel. The decompression system is new and gives more stable operation at low rpm, increasing stall-resistance. And the clutch has an extra plate and is also now hydraulic, improving both control and feel at the lever.
OBJECTIVES
The development theme of the 2021 CRF450R—”Razor Sharp Handling”—was very well-suited for the CRF450RX, given its intended application of technical trails typically found in closed-course off-road competition. This theme was founded on three main goals: Improve power, improve handling and improve consistency. The first point was addressed by making changes intended to increase the engine’s horsepower and torque, particularly in the bottom end of the range. The second objective was addressed by optimizing chassis rigidity, altering geometry and reducing vehicle weight. The final goal—regular, steady performance by both the machine and the rider—was pursued via updates to the clutch, as well as the vehicle layout for improved rider movement.
As is often the case, benefits overlapped, with improvements in one area leading to benefits in other areas. For example, the power and torque increase result in changes to power delivery that make the machine more manageable in corners. Similarly, the reduced weight not only aids cornering, but promotes a more consistent performance by the rider over the course of a race.
Speaking of weight savings, the reduction here is an example of something that was only achievable during an overall redesign, and only by accumulating small benefits in myriad areas. As the Japanese saying goes, “With enough dust, a mountain can form,” and in this case the mountain was represented by a 4 pound overall weight reduction compared to last year’s model.
2021 Honda CRF450RX Totalmotorcycle.com Features and Benefits
ENGINE / DRIVETRAIN
The CRF450RX engine has undergone a number of significant updates aimed at improving bottom-end and midrange power, making for a linear delivery that is strong but manageable, even as the rider tires. In addition, peak power is up .8 horsepower, above 5,000 rpm.
Head
The design of the Unicam® cylinder head has been updated, with the decompressor system’s counterweight relocated from the right end of the camshaft to the left. This improves combustion stability in the extremely low rpm range and contributes to a strong-but-manageable power delivery in corner exits, for example, as well as resistance to stalling. The magnesium cylinder head cover has also been designed with a thinner material, for weight savings.
In addition, the exhaust port has been centralized, ovalized and straightened, achieving improved exhaust efficiency and revised torque characteristics, for a linear delivery that continues into the high rpm range.
As before, a five-hole piston oil jet and dual 12mm drum scavenge pump manage lubrication.
Intake
The CRF450R features a downdraft intake design that delivers strong, efficient power, but the air boot has been drastically enlarged (from 1.8 liters on the clean side of the air filter to 4.1 liters), resulting in better torque at low rpm. In addition, the rubber ring has been eliminated to simplify filter cleaning, with an external frame added to ensure a good seal is maintained. The air box is now accessed with the removal of a single side-panel bolt.
The angle of the fuel injector has been increased from 30º to 60º, enabling the spray to reach all the way to the back of the butterfly, thus cooling the upstream side of the intake path, improving intake efficiency and torque feel.
In addition, the fuel pump is now smaller and 120 grams lighter. It’s affixed via a simplified mounting system using only four fasteners instead of six. Fuel pressure and filter life are both unaffected.
Exhaust
For 2021, the CRF450RX makes the switch from two mufflers to one, reducing weight and improving bottom-end torque delivery. The entire exhaust system now weighs 8.5 pounds, a reduction of 2.7 pounds from the previous model.
With the engine’s new centralized exhaust-port location, the exhaust header is now routed 74 mm closer to the engine on the right side, while the single, right-side muffler has also been reshaped to move its outer surface 13 mm inboard. The combined result is a slimmer overall vehicle body (including external parts), contributing to freedom of movement for the rider.
Two resonators (one after the front U-bend and another at the upstream end of the muffler) boost power and reduce noise, and the heat shield has been eliminated to reduce weight.
Clutch
With an eye toward increasing clutch durability, engineers increased clutch volume by 27% while also adding an eighth clutch plate and using stiffer springs. In addition, a friction spring was added to suppress resonance and greatly improve power delivery. These changes reduce clutch slip by 85% at peak power, as measured by a chassis dynamometer.
To facilitate clutch actuation and encourage consistent performance, a hydraulic clutch is now utilized as on the HRC factory machines. As a result, the force needed to pull the handlebar lever is reduced. Depending on where in the lever stroke the measurement is taken, the reduction can be as much as 10% compared to the previous model, even with the stiffer springs.
Electronics
A gear-position sensor allows the use of three specific ignition maps for first and second, third and fourth, and fifth gears. There are also options for Standard, Smooth and Aggressive ignition maps, selectable via a separate handlebar-mounted switch, enabling simple tuning depending on rider preference or course conditions.
In addition, Honda Selectable Torque Control still offers three levels of intervention. HSTC monitors rpm spikes and responds by temporarily reducing torque by retarding ignition timing and controlling PGM-FI to aid rear traction. The three different modes differ in drive-management level, for differing riding conditions or rider preferences:
- Mode 1: The system intervenes most lightly, and waits the longest to do so—useful for reducing wheel-spin and maintaining control in tight corners.
- Mode 2: A midpoint between modes 1 and 3 in terms of how quickly and assertively the system intervenes.
- Mode 3: The system intervenes most quickly and assertively, which helps in slippery or muddy off-road conditions.
A handlebar-mounted switch allows selection between three modes, depending on conditions and rider preference. The HSTC system can also be switched off completely.
HRC Launch Control provides the best option for a strong start and also has three modes to choose from:
- Level 1: 9,500 rpm, for high-traction conditions and/or advanced riders
- Level 2: 8,500 rpm, for high-traction conditions and/or average riders
- Level 3: 8,250 rpm, for slippery conditions and/or novice riders
The Engine Mode Select Button (EMSB) alters the engine’s characteristics and three maps are available to suit riding conditions or rider preference:
- Mode 1: Standard
- Mode 2: Smooth
- Mode 3: Aggressive
CHASSIS / SUSPENSION
A number of significant chassis revisions were incorporated in order to improve cornering. With these changes, geometry is now different: Wheelbase is now 1 mm shorter (at 58.3.0 inches), rake is relaxed .5º (at 27.7º), trail is reduced by 2 mm (now 114 mm), the swingarm angle is .9º steeper (at 14.5º), the seat height is 5 mm taller (at 38.0 inches), ground clearance is increased by 8 mm (now 13.2 inches), and the distance from the front axle to the swingarm pivot is 1.8 mm longer (at 36.0 inches). As before, the vehicle’s heavier components are positioned centrally and as low as possible.
The result is improved cornering without sacrificing high-speed tracking, in addition to reduced squat under acceleration and less pitching during hard braking.
Frame / Swingarm / Subframe
An all-new frame uses narrower main spars, a redesigned downtube and features rearranged reinforcement ribbing on the backside of the pivot plate, changes that contribute to an overall weight reduction of 1.54 pounds, with the new frame weighing just 18.5 pounds. Lateral rigidity is reduced by 20%—resulting in supple feel that improves cornering—while vertical rigidity is maintained.
The subframe features a simplified design that enabled the elimination of a separate seat support, achieving an overall weight of just 2.0 pounds—over .7 pounds down from before.
In addition, the swingarm is now narrower, providing increased clearance in ruts, with rebalanced rigidity tuned to match the frame and improve rear traction and cornering.
Suspension
As before, front suspension comprises a 49 mm inverted Showa® coil-spring fork that follows the basic structure of that on the 2020 CRF450RX, and a gas-liquid separation structure, but suspension stroke has been increased by 5 mm to better absorb rough terrain while also reducing pitching. In addition, the axle holders have an updated design for increased rigidity. The upper and lower triple clamps have both been redesigned as well, with rigidity rebalanced via updated reinforcement ribs, delivering increased flex characteristics for improved handling and feel through a corner.
The Pro-Link® rear-suspension system uses a Showa shock absorber whose shape has been adapted to work with the new frame, with adjusters moved from the left side to the right. Weight was cut here as well, by switching to a lightweight steel shock spring.
The link ratio and rear travel has also been changed so that acceleration-triggered rear-end squat is reduced.
Wheels
As before, black D.I.D. rims deliver durable performance and good looks. Petal-style brake rotors disperse heat, and a low-expansion front brake hose gives strong feel and consistent stopping power.
The 2021 CRF450RX comes with Dunlop’s excellent Geomax AT81 tires, which offer all-around performance and high levels of ruggedness for off-road racing.
DESIGN
The technical changes to the CRF450RX enabled the adaptation of slimmer bodywork, which facilitates rider movement. For example, the lack of a left-side muffler made possible a side panel that is 50 mm more inboard, and even the right side panel is moved 20 mm inboard thanks to the new muffler shape. Together, the changes result in a 70 mm reduction in width at the rear of the bike, substantially benefitting rider movement—and, consequentially, cornering. The junction of the radiator shroud and the side panel is smoother as well, further aiding rider movement.
The radiator shrouds are new as well, and each is now produced in a single piece instead of two separate parts. Computational Fluid Dynamics (CFD) were used to design new air-outlet vents in the shrouds. The radiator grills have also been revised to optimize the number of fins and their angle, resulting in a 5% improvement in cooling performance, while the vehicle width is actually 17.7 mm narrower at the front of the shrouds, thanks to redesigned 2.1 gallon, polyethylene fuel tank offering just .1 gallons less capacity from before.
Whereas the seat was previously installed by sliding it forward onto the subframe and then securing it at the rear, the new seat base has rearward-facing tongues and front-located mounting tabs. This eases installation, and acceleration forces keep the seat securely in place.
During the model’s redesign, engineers looked for and capitalized upon every opportunity to cut weight for improved handling. For example, only 8 fasteners are used to secure all of the main bodywork components—both radiator shrouds, both side panels and the seat—instead of 12 as before. In addition, all of the bolts for the main bodywork parts now have 8 mm heads, simplifying maintenance.
A further 98 grams were cut by combining what used to be two left-side handlebar switch assemblies into a single cluster that addresses several functions: engine stop, ride-modes and Honda Selectable Torque Control (HSTC). The starter and HRC launch control are on the right side of the Renthal® Fatbar® handlebar. As before, there are two locations for the handlebar clamp, and the clamp can be turned 180º; as a result, four different mounting positions are possible, through a range of 26 mm. Routing the throttle and clutch control cables behind the handlebar instead of in front allowed for a weight reduction of 100 grams high on the bike.
Off-Road Features
As always, the 2021 CRF450RX comes with a number of off-road-appropriate features that are not included on its motocross-focused CRF450R sibling.
The ECU map is developed to aid traction in technical off-road conditions, and the suspension settings are more supple than the CRF450R, to minimize deflection off rocks and roots. A forged-aluminum side stand comes standard, as does an 18-inch rear wheel and 50-tooth rear sprocket compared to the R’s 49.
New for 2021 are plastic handguards, to protect knuckles and levers from impacts when riding through brush. A pair of handguards, which weigh only 222 grams, can be easily removed.
Combine the model’s off-road-focused features with the platform’s performance updates for 2021 and you have a machine that’s more ready than ever to chase arrows and ribbon along trails from coast to coast.
2021 Honda CRF450RX – Totalmotorcycle.com USA Specifications/Technical Details
US MSRP Price: $9899 USD
Canada MSRP Price: $10,899 CDN
Europe/UK MSRP Price: £ GBP (On The Road inc 20% Vat)
| ENGINE | ||
| Type | 449.7cc liquid-cooled 10º single-cylinder four-stroke | |
| Valve Train | Unicam® OHC, four-valve; 38mm intake, steel; 31mm exhaust, steel | |
| Bore x Stroke | 96.0mm x 62.1mm | |
| Compression Ratio | 13.5:1 | |
| Induction | Programmed fuel-injection system (PGM-FI); 46mm throttle bore | |
| Ignition | Full transistorized | |
| Starter | Push-button electric starter | |
| Transmission | Constant-mesh 5-speed return; manual | |
| Clutch | Multiplate wet, hydraulically actuated (6 springs) | |
| Final Drive | #520 sealed chain; 13T/50T | |
| SUSPENSION | ||
| Front | 49mm fully adjustable leading-axle inverted telescopic Showa coil-spring fork w/ 12.2 in. travel | |
| Rear | Pro-Link system; fully adjustable Showa single shock w/ 12.32 in. travel | |
| BRAKES | ||
| Front | 2-piston caliper (30mm, 27mm) hydraulic; single 260mm disc | |
| Rear | 1-piston caliper hydraulic; single 240mm disc | |
| TIRES | ||
| Front | Dunlop Geomax AT81 90/90-21 w/ tube | |
| Rear | Dunlop Geomax AT81 120/90-18 w/ tube | |
| MEASUREMENTS | ||
| Rake (Caster Angle) | 27°7’ | |
| Trail | 114mm | |
| Length | 85.9 in. | |
| Width | 33 in. | |
| Height | 50.5 in. | |
| Ground Clearance | 13.2 in. | |
| Seat Height | 38 in. | |
| Wheelbase | 58.3 in. | |
| Fuel Capacity | 2.1 gal. | |
| Color | Red | |
| Curb Weight* | 251 lbs. | |
*Includes all standard equipment, required fluids and full tank of fuel—ready to ride
Specifications subject to change
2021 Honda CRF450RX – Totalmotorcycle.com Canada Specifications/Technical Details
Engine & Drivetrain
Engine Type Liquid-cooled single-cylinder 4-stroke
Displacement 449.8 cc
Bore & Stroke 96 mm x 62.1 mm
Compression Ratio 13.5:1
Valve Train Unicam, 4 valves
Fuel Delivery PGM-FI electronic fuel injection with 46 mm throttle body
Transmission Close-ratio, five speed
Final Drive #520 sealed chain; 13T/50T
Chassis & Suspension
Front Suspension Showa 49 mm telescopic inverted coil spring with rebound and compression damping adjustability. 310 mm (12.2 in ) travel.
Rear Suspension Pro-Link® Showa single shock with adjustable spring preload, rebound damping adjustability, and compression damping adjustment separated into low-speed and high-speed; 313 mm (12.3 inches) travel
Dimensions & Additional Information
Tires Front: 90/90-21
Rear: 120/90-18
Brakes Front: 260 mm disc with dual-piston caliper
Rear: 240 mm disc
Ground Clearance 336 mm (13.2 in.)
Seat Height 965 mm (38 in.)
Wheelbase 1,481 mm (58.3 in.)
Curb Weight 114 kg (251 lb.) including required fluids and full tank of gas—ready to ride
Fuel Capacity 8 litres
Colour Extreme Red
Warranty No warrranty
2021 Honda CRF450RX – Totalmotorcycle.com European Specifications/Technical Details
Engine
Bore × Stroke (mm) 96.0mm x 62.1mm
Carburation CDI Electronic Fuel injection
Compression Ratio 13.5 : 1
Engine Displacement (cc) 449.7cc
Engine Type Liquid-cooled 4-stroke single cylinder uni-cam
Starter Electric
Oil Capacity (Litres) 1.25 Litres
Wheels
Brakes Front Single 260mm disk
Brakes Rear Single 240mm disk
Suspension Front Showa 49mm USD fork
Suspension Rear Showa monoshock using Honda Pro-Link
Tyres Front Dunlop Geomax AT81F
Tyre Size Front 90/90-21M
Tyre Size Rear 120/90-18M
Tyres Rear Dunlop Geomax AT81
Wheels Front Aluminium spoke
Wheels Rear Aluminium spoke
Dimensions and Weights
Caster Angle 27.2°
Dimensions (L×W×H) (mm) 2,182mm x 839mm x 1,282mm
Frame type Aluminium twin tube
Fuel Tank Capacity (Litres) 8 litres
Ground Clearance (mm) 336mm
Kerb Weight (kg) 113.4kg
Seat Height (mm) 965mm
Trail (mm) 115mm
Wheelbase (mm) 1,477mm
Transmission
Clutch Wet type multi-plate
Final Drive Chain
Transmission Type Constant mesh
Manufacturer Specifications and appearance are subject to change without prior notice on Total Motorcycle (TMW).
